Carpet cleaning systems of the general configuration of the present invention are well known. The use of a separate base and mobile unit is common as it reduces the weight of the mobile unit which the user must manipulate. Many such systems, however, rely on brushes or fixed cleaning nozzles to do the actual cleaning. The use of fixed nozzles is effective, but limited in that a particular spot on the carpet is typically treated only a single time, by a single nozzle.
A previous patent, U.S. Pat. No. 4,191,589 to Halls et al discloses a mobile unit comprising rotating arms with fixed nozzles positioned at the ends of the arms. That system improves on the fixed nozzle systems in that a particular spot will be addressed many times as the nozzles rotate past. The rotary motion of the arms is imparted by the force of the cleaning fluid exiting the nozzles. As such, the arm rotates in a direction away from the direction of the cleaning fluid jet. One embodiment of the system comprised a single nozzle which pointed in the direction of rotation. Its force then has to be overcome by the force of the remaining jets so that the arm will rotate. That system also incorporates a vacuum pickup at the front edge, supplemental rinse nozzles positioned behind the vacuum pickup, and a base unit comprising the vacuum and pressure pump subsystems. The use of fluid pressure at the nozzles to impart the rotary motion is convenient and advantageous in that the unit can be made much lighter since no mechanical drive train is required. However, the efficiency of the cleaning is compromised. A majority of the jets must move away from the direction of the fluid jet, reducing their effectiveness. The fluid pressure and nozzle angles must be selected so as to impart the desired rotational speed. The arm, and nozzles, are in motion only when cleaning fluid is being emitted. A "spin up" delay is required when the cleaning fluid is activated to allow the arm to attain its rotation speed, During this delay, cleaning ability is compromised, and it may be necessary to hold the unit in a stationary position, wasting cleaning fluid, time, and possibly over exposing the surface to cleaning fluid, leading to saturation.
Windsor Industries Inc., Englewood, CO has reportedly sold a cleaning system in which a motor drive is used to rotate an arm with a set of fixed heads in the direction of the fluid jet. This design overcomes some of the problems of the pressure driven system but still falls short of an ideal system. All of the jets in this system point in the same direction and rotate in the same direction. Further, the coverage pattern is a simple circular one which can lead to skips and striping.
Various types of rotary brush floor cleaners are also well known. These are typically designed for use on hard surfaced floors. While usable on certain short-napped carpets, they are not generally applicable to carpeted surfaces.
There is a need for a cleaning system which utilizes pressurized cleaning fluid applied from a series of rotating nozzles wherein the motion of the nozzles and the pressure and angle of the cleaning fluid jets are not interrelated. The nozzles should travel in a complex pattern such as that provided by rotating heads mounted to a separately rotating arm. Preferably the pressure at which the fluid is emitted and the angle at which it is emitted can be varied without effecting the rotational speed of the supporting arm. Preferably, the nozzles will move in the same direction in which the cleaning jet is emitted, rather than away from it. Ideally, plural heads will be provided which rotate in opposite directions, providing alternating directions for the fluid jet. Ideally, fluid pressure and temperature, rotational speed, and nozzle angle can all be adjusted by the end user of the system, either via a control on the base unit, remote wireless or corded control on the mobile unit, or by interchanging components of the system. Such a system should be usable on a variety of surface including carpeted and hard surfaced floors